Cast reinforced housing and method of making the same

ABSTRACT

A cast reinforced housing comprises a cast peripheral housing wall defining an interior chamber for the components of an apparatus and preferably consisting of cast aluminum. At least one reinforcing embedment is provided in the wall and consists of a material having greater strength than the material of the wall, for example steel.

United States Patent 1 Haag et al.

[451 July 17,1973

[ CAST REINFORCED HOUSING AND METHOD OF MAKING THE SAME [75] inventors:Robert Hang, Stuttgart-Bad I Cannstatt; Albert Haupt,

Oberriexingen; Siegfried Mayer, Kleinglattbach, all of Germany [73]Assignee: Robert Bosch GmbII, Stuttgart,

Germany 22 Filed: Aug. 25, I970 211 Appl. No.: 66,741

[30] Foreign Application Priority Data Sept. 27, [969 Germany P 19 49033.6

521 i I 74/6011, 164/98 [51] Int. Cl. Fl6h 57/02 [58] Field of Search74/606 R; 164/111, 164/98 [5 6] References Cited UNITED STATES PATENTSDake l64/l ll 3,263,521 8/1966 Miiller 74/606 R OTHER PUBLICATIONSMarks, Lionel S. Mechanical Engineers Handbook,

4th Ed. N.Y., McGraw-Hill Book Co. Inc, I941, p. 420-42l.

Primary Examiner-Charlcs .l. Myhrc Assistant ExaminerF. D. ShoemakerAttorney-Michael S. Striker [57] ABSTRACT 'A-cast reinforced housingcomprises a cast peripheral housing wall defining an interior chamberfor the components of an apparatus and preferably consisting of castaluminum. At least one reinforcing embedment is provided in the wall andconsists of a material having greater strength than the material of thewall, for example steel.

ll Claims, 3 Drawing Figures EAST REINFORCED HOUSING AND METHOD OFMAKING THE SAME BACKGROUND OF THE INVENTION The present inventionrelates generally to housings, and more particularly to cast housings.Still more particularly the invention relates to a cast housing for agear-driven apparatus such as gear pumps or gear motors.

Housings for such gear-driven apparatus are of course already known,just as it is known to make such housings of cast aluminum. They arecast in suitably configurated molds and a known housing of this type hasan inner space for accommodating the constituent components of theapparatus, which space is formed by two cylindrical bores partiallyoverlapping one another. This known housing can be manufactured veryeconomically and has therefore found wide acceptance. It does, however,have the disadvantage that it its walls are made with a thickness withinacceptable limits- -and of course thus within-acceptable external dimensions for the housing overall-the strength of the walls is relativelylow so that the housing can be used only under relatively insubstantialpump pressures if the housing is used in connection with a gear pump.

Evidently it would be desirable to be able to use such a housing-whichis economically advantageous from the point of view of manufacture andselling-for applications where it must withstand greater stresses.

SUMMARY OF THE INVENTION It is, accordingly, an object of the inventionto provide an improved housing of the type under discussion.

More particularly it is an object of the present invention to providesuch a housing which has substantially improved strength characteristicsespecially resistance to tensile stress on a continuous basis, over whatis known from the art, given identical or substantially identical wallthickness.

In pursuance of the above objects, and others which will become apparenthereafter, one feature of the invention recites in a housing,particularly for geardriven apparatus, which comprises briefly stated acast peripheral housing wall defining an interior chamber for thecomponents of said apparatus and consisting of a first materialpermitting manufacture of said wall as a casting-At least onereinforcing embedment is provided in the wall and consists of a secondmaterial having greater strength characteristics than the firstmaterial.

By producing a housing according to the invention,

the stresses, particularly the tensile stresses acting upon theperipheral housing wall as a result of internal pressure developing inthe housing space or chamber, are to at least a substantial extenttransmitted into and withstood by the reinforcing embedment, thusrelieving the lower-strength peripheral housing wall and making the thusproduced housing'capable of withstanding substantially greater stressesthan a similar housing without expansion and contraction which at leastapproximates that of the material for the peripheral housing wallitself.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly sectionedperspective view illustrating a housing according to the presentinvention;

FIG. 2 is an end-elevational rather diagrammatic view illustrating afurther embodiment of the invention; and

FIG. 3 is a top-plan view of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail, and firstly the embodiment illustrated in FIG. 1 thereof, itwill be seen that reference numeral 1 generally identifies the novelhousing in toto. For purposes of explanation the housing in FIG. 1 shallbe assumed as intended to house a gear pump. It is cast of an aluminumalloy in a suitably configurated mold in a known manner.

The housing It has an external contour composed of several cylindricalsurfaces and is provided with an internal or interior chamber 2 which isopen at opposite ends and defined in essence by two substantiallycylindrical bores which extend in axial parallelism with one another andwhich partially overlap. In the region of the overlap there are providedtwo concavely configurated interior surface portions 3 and 4. An inletopening 5 is provided normal to the plane intersecting the axis of thetwo parallel bores or cylinders whose imaginary outlines together definethe interior chamber 2; this inlet is provided in one side wall of thehousing ll whereas the pump outlet 6 is provided in the opposite sidewall of the housing 1. Pairs of apertures or bores 7 are provided ineach side wall which permit the passage of bolts or other suitablefastening means for securing to the housing the non-illustrated coverswhich close off the opposite ends of the chamber 2.

According to the present invention the circumference or peripheral wallof the housing Ill-consisting of cast aluminum-is provided withreinforcing embedments b, 9 and W which here are assumed to be of steeland which together constitute in effect a supporting structure. Theembedment 8 is in form of a sheet-steel tube 8 of substantially ovalcross-section which is so large that in the illustrated embodiment thedistance between the inner surface of the tube 8 and the inner surfaceof the wall of the housing ll bounding the chamber 2 is approximately 2mm; meaning that approximately a thickness of 2 mm of cast aluminumexists between the inner surface bounding the chamber 2 and the tube 8.The tube d is provided with circular cutouts 5' and 6' whichrespectively register with the inlet 5 and the outlet 6 in the housingwall; their diameter is approximately 4 mm larger than the diameter ofthe inlets 5 and 6, respectively.

At each of its opposite ends the tube 9 is provided with a flange ofsheet metal, respectively identified with reference numerals 9 and andprovided with cutouts 7' which register with the apertures 7. Thesecutouts 7' surround the associated apertures 7 with approximately 1-2 mmspacing.

it will be appreciated that in FIG. 1 the outlines of the reinforcingembedments 8, 9 and 10 have been shown in solid heavy lines for purposesof better understanding only; naturally these outlines would notnormally be visible inasmuch as the embedments 8, 9 and 10 arecompletely embedded within the cast aluminum material of the housingwall 1 and would not be visible at all. However, it is thought thatunderstanding will be facilitated by the illustration which has beenchosen.

Coming to the embodiment illustrated in FIGS. 2 and 3 it will be seenthat here a planar strip of sheet metal is provided with cutouts 5' and6' for registration with the pump inlet and pump outlet, respectively;this cutout has been formed to the shape of a tube having asubstantially oval cross-section and identified with reference numeral11. Near the edge or end of the tube and positioned on the long axis ofthe oval are provided short sheet metal portions which are stamped orotherwise displaced out of the sheet material of the tube 11 and so bentupwardly that abutments 12 are obtained. These are most clearlyillustrated in FIG. 3 and it will also be seen that at each longitudinaledge of the tube 11 a flange 13 and 14, respectively, press againstthese abutments 12. The flanges in turn are provided with cutouts 7'which register with the apertures 7 (shown in FIG. 1).

The various cutouts are provided on the material of the tube 11 beforethe latter is cast or embedded in the peripheral housing wall. Thismakes it possible for the tools subsequently used for finishing thehousing to find a homogenous material composition, that is tools such asdrills, gear cutters or the like.

In this embodiment, as in the one shown in FIG. 1, the diameter of thecutouts in the embedments is made larger than the diameter of theapertures provided in the housing with which they must register, becausethis assures that even after mechanical working of the housing itself,for instance after cutting gears into the material in the inlet andoutlet or the like, a certain amount of the basic material of thehousing wall--i.e., cast aluminum in the illustrated embodiments-willremain inwardly of the material of the tube 8 or 11. This assumes, ofcourse, that the embedments are positioned in the casting mold with anofi'set which is in normal tolerance variations.

It will be appreciated that the housing may be substantially cup-shaped,that is that the chamber may be open at one end rather than at bothends, and that other configurations are also possible. It will furtherbe appreciated that any or all of the embedments may be perforated orapertured so that the material of the housing wall, such as castaluminum, can flow into these apertures and establish a stronger andstill more intimate bond between the housing wall and the embedments.Such apertures may of course have various desired sizes andconfigurations.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in ahousing for a gear-driven apparatus, it is not intended to be limited tothe details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A housing, particularly for a gear-driven apparatus, comprising acast peripheral housing wall having an interior surface defininginwardly of said surface an interior chamber for the components of saidapparatus and consisting of a first material permitting manufacture ofsaid wall as a casting; and at least one embedment in said peripheralwall located in its entirety behind and outwardly of said interiorsurface and consisting of a second material having greater strengthcharacteristics than said first material.

2. A housing as defined in claim 1, wherein said embedment is asheet-metal insert.

3. A housing as defined in claim 1, wherein said embedment is a tubularmember provided with opposite apertures intermediate its ends.

4. A housing as defined in claim 1, wherein said first material is castaluminum, and wherein said second material is steel.

5. A housing as defined in claim 1, wherein said first material has apredetermined coefficient of thermal expansion, and wherein said secondmaterial has a coefficient of thermal expansion which at leastapproximates said predetermined coefficient.

6. A housing as defined in claim 1, said embedment being substantiallycompletely embedded in said first material.

7. A housing as defined in claim 1, at least part of said embedmentbeing substantially completely embedded in said first material.

8. A housing as defined in claim 1, wherein said second material has agreater tensile strength than said first material.

9. A housing, particularly for a gear-driven apparatus, comprising acast peripheral housing wall defining an interior chamber for thecomponents of said apparatus and consisting of a first materialpermitting manufacture of said wall as a casting; and at least onereinforcing embedment in said wall and consisting of a second materialhaving greater strength characteristics than said first material, saidembedment being a tubular member slit along a generatrix thereof andhaving spaced ends, and having a flange-shaped portion provided on atleast one of said ends.

10. A housing, particularly for a geardriven apparatus, comprising acast peripheral housing wall defining an interior chamber for thecomponents of said apparatus and consisting of a first materialpermitting manufacture of said wall as a casting; and at least onereinforcing embedment in said wall and consisting of a second materialhaving greater strength characteristics than said first material, saidwall and said embedment each having at least one registering aperture,with that 0nd material having greater strength characteristics than saidfirst material, said embedment being provided with apertures filled bythe material of said wall whereby the latter and said embedment areinterlocked against forces tending to cause them to perform movementsrelative to one another.

1. A housing, particularly for a gear-driven apparatus, comprising acast peripheral housing wall having an interior surface defininginwardly of said surface an interior chamber for the components of saidapparatus and consisting of a first material permitting manufacture ofsaid wall as a casting; and at least one embedment in said peripheralwall located in its entirety behind and outwardly of said interiorsurface and consisting of a second material having greater strengthcharacteristics than said first material.
 2. A housing as defined inclaim 1, wherein said embedment is a sheet-metal insert.
 3. A housing asdefined in claim 1, wherein said embedment is a tubular member providedwith opposite apertures intermediate its ends.
 4. A housing as definedin claim 1, wherein said first material is cast aluminum, and whereinsaid second material is steel.
 5. A housing as defined in claim 1,wherein said first material has a predetermined coefficient of thermalexpansion, and wherein said second material has a coefficient of thermalexpansion which at least approximates said predetermined coefficient. 6.A housing as defined in claim 1, said embedment being substantiallycompletely embedded in said first material.
 7. A housing as defined inclaim 1, at least part of said embedment being substantially completelyembedded in said first material.
 8. A housing as defined in claim 1,wherein said second material has a greater tensile strength than saidfirst material.
 9. A housing, particularly for a gear-driven apparatus,comprising a cast peripheral housing wall defining an interior chamberfor the components of said apparatus and consisting of a first materialpermitting manufacture of said wall as a casting; and at least onereinforcing embedment in said wall and consisting of a second materialhaving greater strength characteristics than said first material, saidembedment being a tubular member slit along a generatrix thereof andhaving spaced ends, and having a flange-shaped portion provided on atleast one of said ends.
 10. A housing, particularly for a gear-drivenapparatus, comprising a cast peripheral housing wall defining aninterior chamber for the components of said apparatus and consisting ofa first material permitting manufacture of said wall as a casting; andat least one reinforcing embedment in said wall and consisting of asecond material having greater strength characteristics than said firstmaterial, said wall and said embedment each having at least oneregistering aperture, with that in said embedment being at least equalin size and dimension to that in said wall.
 11. A housing, particularlyfor a gear-driven apparatus, comprising a cast peripheral housing walldefining an interior chamber for the components of said apparatus andconsisting of a first material permitting manufacture of said wall as acasting; and at least one reinforcing embedment in said wall andconsisting of a second material having greater strength characteristicsthan said first material, said embedment being provided with aperturesfilled by the material of said wall whereby the latter and saidembedment are interlocked against forces tending to cause them toperform movements relative to one another.